A conventional color printer as an electro-photographic type printer includes a photosensitive body configured to carry a toner image, and a developing cartridge provided with a developing roller as a developer carrier configured to supply toner to the photosensitive body.
Japanese Patent Application Publication 2010-197777 discloses such a conventional developing cartridge including a metallic electrode plate to which an electric power is supplied from an external power source in a casing of the printer, and an electrically conductive bearing member electrically connected to the electrode plate and rotatably supporting a shaft of the developing roller.